1. Field of the Invention
The present invention relates to a staged oxidation chamber where a sample and an oxidizing agent are introduced into a oxidation chamber to form an oxidizing mixture and subsequently at least another portion of oxidizing agent is introduced to the oxidizing mixture to enhance oxidation and the production of nitrogen and/or sulfur oxides for subsequent detection.
More particularly, the present invention relates to a multi-staged combustion chamber where an influent of a sample and excess oxidizing agent are introduced into the chamber maintained at an elevated temperature to form an oxidizing mixture and subsequently at least one additional portion of oxidizing agent is introduced to the oxidizing mixture which results in enhanced oxidation efficiency, enhanced liberation and oxidation of chemically bound nitrogen and/or sulfur and improved detection sensitivity for nitrogen, sulfur, chlorides and/or phosphorus.
2. Description of the Related Art
Many analytical systems require conversion of the chemical components into derived chemical components that are capable of detection in a given detection device. Often the conversion requires partial to complete conversion of the chemical components to their oxides. Generally, this is accomplished by combustion of the chemical components in the presence of an oxygen containing gas. However, when the chemical components to be oxidized include large amount of hydrocarbons and small amount of elemental constituents that are of interest, then oxidation efficiency becomes a significant impediment to detectability and ultimate detection limits and sensitivities
Thus, oxidation or combustion chambers that improve oxidation or combustion efficiencies represent an advancement in the art especially relating to the detection of small elemental constituents such as nitrogen, phosphorus and/or sulfur where highly efficient oxidation greatly enhances detection reproducibility, sensitivity and detection limits.
The present invention provides a multi-staged combustion or oxidation device including a combustion tube having a sample introduction line and at least two oxidizing agent introduction lines. The sample introduction line and an inert gas introduction line are associated with a device inlet where the inert gas carries the sample into a first combustion zone where the sample and carrier are mixed with a first amount of oxidizing agent from the first oxidizing agent introduction line to form an oxidizing mixture. The second oxidizing agent introduction line is located a distance d downstream from the first combustion zone and supplies a second amount of oxidizing agent to the mixture in a second combustion zone to enhances combustion of the sample and liberation of nitrogen, phosphorus and/or sulfur oxides. Additional oxidizing agent introduction lines can also be included in the device.
The present invention provides a multi-staged combustion or oxidation device including a combustion tube having a sample introduction line and at least two oxidizing agent introduction lines. The sample introduction line and one of the oxidizing agent introduction lines are associated with a device inlet and the second oxidizing agent introduction line is located a distance d downstream from the inlet which establishes two combustion zones. Additional oxidizing agent introduction lines can also be included in the device.
The present invention provides a multi-staged combustion or oxidation device including a combustion tube having a sample introduction line and at least two oxidizing agent introduction lines. The sample introduction line and one of the oxidizing agent introduction lines are associated with an interface operably connected to a device inlet and the second oxidizing agent introduction line is located a distance d downstream from the inlet which establishes two combustion zones. Additional oxidizing agent introduction lines can also be in included in the device.
The present invention also provides nitrogen, phosphorus and/or sulfur detection systems with improved sensitivity, detection limits and reproducibility incorporating one of the above-described combustion devices.
The present invention further provides detection systems including an oxidation device of the present invention designed for direct injection or optionally coupled to a separation device by an interface and a post oxidation device transformation device coupled to a detection system.
The present invention also provides methods for enhanced detection of nitrogen, phosphorus and/or sulfur present in a sample where the method incorporates sample oxidation in a multi-staged combustion device of the present invention.